Congress wanted the list to name and shame those who had benefited from close association with President Putin and put them on notice that they could be targeted for sanctions, or more sanctions, in the future.

President Donald Trump did not support Caatsa, even though he signed it into law, saying it was "unconstitutional".

Under the law, the list had to be delivered by Monday. The fact it was released about 10 minutes before midnight may reflect Mr Trump's coolness towards it, and his opposition to punishing more Russians with sanctions.

Who has been named?

Informally known as the "Putin list", the unclassified section has 210 names, 114 of them in the government or linked to it, or key businessmen. The other 96 are oligarchs apparently determined more by the fact they are worth more than $1bn (£710m) than their close ties to the Kremlin.

REUTERS
Congress passed the law in August, although President Donald Trump had opposed it

Most of Mr Putin's longstanding allies are named, many of them siloviki (security guys). They include the spy chiefs Alexander Bortnikov of the Federal Security Service (FSB) - which Mr Putin used to run - and Sergei Naryshkin of the Foreign Intelligence Service (SVR).

The men who control Russia's energy resources are listed: Gazprom chief Alexei Miller, Rosneft chief Igor Sechin and other oil and gas executives, along with top bankers like Bank Rossiya manager Yuri Kovalchuk.

Internationally known oligarchs are there too, such as those with stakes in top English football clubs: Alisher Usmanov (Arsenal) and Roman Abramovich (Chelsea).

Will they face new sanctions?

Not at the moment. The US Treasury document itself stresses: "It is not a sanctions list, and the inclusion of individuals or entities... does not and in no way should be interpreted to impose sanctions on those individuals or entities."

It adds: "Neither does inclusion on the unclassified list indicate that the US government has information about the individual's involvement in malign activities."

However, there is a classified version said to include information detailing allegations of involvement in corrupt activities.

What is the Caatsa act and did the president want it?

The law limited the amount of money Americans could invest in Russian energy projects and made it more difficult for US companies to do business with Russia.

It also imposed sanctions on Iran and North Korea.

Media captionAll you need to know about the Trump-Russia investigation

In signing the act, Mr Trump attached a statement calling the measure "deeply flawed" and said he could make "far better deals with foreign countries than Congress".

Earlier on Monday, the US government argued the Caatsa law had already pushed governments around the world to cancel deals with Russia worth billions, suggesting that more sanctions were not required.

How have the Russians reacted?

Perhaps referring to the fact that all of their political representatives had been named, Mr Putin said that, in effect, "all 146 million Russians have been put on the list".

He joked he was offended not to be named himself.

Earlier, Kremlin spokesman Dmitry Peskov, who is himself on the list, accepted that it was not one of sanctions but said it could potentially damage "the image and reputation" of figures listed and their associated companies.

He added: "It's not the first day that we live with quite aggressive comments made towards us, so we should not give in to emotions."